New kid on the solar block

A new type of solar cell, made from a material that is dramatically cheaper to obtain and use than silicon, could generate as much power as today’s commodity solar cells. Solar cells can be made very cheaply but have the downside of being relatively inefficient. Lately, more researchers have focused on developing very high efficiency cells, even if they require more expensive manufacturing techniques. The new material could deliver solar cells that are highly efficient but also cheap to make.

Perovskites have been known for over a century, but no one thought to try them in solar cells until relatively recently. Very good at absorbing light the new solar cells use less than one micrometer of material to capture the same amount of sunlight. The pigment is a semiconductor that is also good at transporting the electric charge created when light hits it.

One group has produced the most efficient perovskite solar cells so far—they convert 15 percent of the energy in sunlight into electricity, far more than other cheap-to-make solar cells. Based on its performance so far, and on its known light-conversion properties, researchers say its efficiency could easily rise as high as 20 to 25 percent, as good as the record efficiencies (typically achieved in labs) of the most common types of solar cells today. Perovskite in solar cells will likely prove to be a “forgiving” material that retains high efficiencies in mass production, since the manufacturing processes are simple.

Perovskites will have difficulty taking on silicon solar cells. The costs of silicon solar cells are falling, and some analysts think they could eventually fall as low as 25 cents per watt, which would eliminate most of the cost advantage of perovskites and lessen the incentive for investing in the new technology. But it might be possible to paint perovskites onto conventional silicon solar cells to improve their efficiency, and so lower the overall cost per watt for solar cells.